Slotted waveguide array antennas

Abstract

A slotted waveguide array antenna includes a plurality of waveguide elements extending in a parallel side-by-side relation, each having a radiating side including a broad wall formed with a plurality of slots, and an asymmetric ridge. The slots are slanted to the longitudinal axis of the antenna in alternating directions and are spaced λg/2 apart such as to offset phase reversal between each pair of adjacent slots.

What is claimed is: 
     
       1. A slotted waveguide array antenna comprising a plurality of waveguide elements extending in a parallel side-by-side relation, each waveguide element having a longitudinal axis, a radiating side including a broad wall formed with a plurality of slots, a non-radiating side opposite to said radiating side, and a single asymmetric ridge in said non-radiating side; characterized in that said single asymmetric ridge is a straight continuous ridge extending parallel to, laterally of, and asymmetrical with respect to, said longitudinal axis of the waveguide element, and in that said slots are slanted to the longitudinal axis of the antenna in alternating directions and are spaced λg/2 apart such as to offset phase reversal between each pair of adjacent slots. 
     
     
       2. The antenna according to claim 1, wherein said antenna includes means for feeding the slanted slots at locations where the ridge traverses the slot, to provide control over the slot impedance and the amount of power fed into each slot, to thereby produce a high dynamic range of the slots. 
     
     
       3. A slotted waveguide array antenna comprising: a plurality of waveguide elements extending in a parallel side-by-side relation, each waveguide element having a longitudinal axis a radiating side including a broad wall formed with a plurality of slots, a non-radiating side opposite to said radiating side, and a single asymmetric ridge in said non-radiating side;   said slots being slanted to the longitudinal axis of the antenna in alternating directions and being spaced λg/2 apart such as to offset phase reversal between each pair of adjacent slots;   said single ridge in all the waveguide elements being a straight continuous ridge extending parallel to, laterally of, and asymmetrical with respect to, said longitudinal axis of the respective waveguide element.   
     
     
       4. The antenna according to claim 3, wherein said slots in each waveguide element are slanted in alternating directions. 
     
     
       5. The antenna according to claim 4, wherein said antenna includes means for feeding the slanted slots at locations where the ridge traverses the slot, to provide control over the slot impedance and the amount of power fed into each slot, to thereby produce a high dynamic range of the slots. 
     
     
       6. The antenna according to claim 3, wherein said plurality of waveguide elements are arranged in pairs, the slots of one waveguide element in each pair being slanted parallel to each other and to the axis of the respective waveguide element, and the slots of the other waveguide element in each pair also being slanted parallel to each other and to the axis of the respective waveguide element, but in the opposite direction to the slots of said one waveguide element of the respective pair. 
     
     
       7. The antenna according to claim 6, further including a first power network for feeding said one waveguide element of all the pairs, a second power network for feeding said other waveguide element of all the pairs, and a phase shifting network between said second power network and said other waveguide element of all the pairs such that: (a) when the two waveguides of each pair are in phase, linear polarization is generated perpendicular to the waveguide axis; (b) when the two waveguides of each pair are out of phase, orthogonal linear polarization is generated; and (c) when the two waveguides of each pair are fed in phase quadrature, circular polarization is generated. 
     
     
       8. A slotted waveguide array antenna comprising a plurality of waveguide elements extending in a parallel side-by-side relation, each waveguide element having a longitudinal axis, a radiating side including a broad wall formed with a plurality of slots, a non-radiating side opposite to said radiating side, and a single asymmetric ridge in said non-radiating side; characterized in that said single asymmetric ridge is a straight continuous ridge extending parallel to, laterally of, and asymmetrical with respect to, said longitudinal axis of the waveguide element.